For determining circuit functionality, stability, and reliability, measurement of internal signals in memory devices, logic circuits, or other integrated circuits is useful. The measurement of internal signals provides information about the operation and function of an integrated circuit; the information can be used to diagnose problems in the operation or design of the integrated circuits. Previously disclosed circuits for measuring periodic signals, as a component of the integrated circuit, are designed for on-chip measurement of skew and jitter in the internal signals. The previously disclosed circuits can detect transitions of the periodic signals but cannot identify whether the transitions are rising or falling transitions.